1. Field of the Invention
The present invention relates to a method of packing gels of different activities together into a liquid chromatographic column.
2. Description of the Prior Art
In recent years, liquid chromatography has been used not only as an analytical means but also as one of the separation means in many fields such as food industry, medical product industry, chemical industry including purification and synthesis of intermediate products, inorganic industry, fiber industry, etc. In such industrial fields, since a large quantity of expensive gels are packed into enormous columns, it is very important to maintain the life of the gels in the columns for a long time. But after a long period of operation in liquid chromatography, impurities accumulate in the columns, and the gel layer near the inlet of the columns is severely contaminated. This lowers the separation performance of the columns and further reduces the treating capacity, causing industrial problems such as an increase in pressure loss, damage of the filter in the columns, etc. Therefore, in order to prevent the occurence of such problems, it is desirable to change the whole quantity of the gel before the contamination becomes severe. However, since such a method consumes a large amount of expensive gels, a means is generally employed wherein only the severely contaminated gel portion near the inlet of the column is discarded and the column is packed again with a mixture of the remaining gel and supplemental high activity gel, or a means is employed wherein the contaminated gel portion is replaced by a high activity gel is employed at the inlet side of the column is employed. Particularly, the gel near the inlet of the column is remarkably contaminated in comparison with the gel at the center or near the outlet, and also the effect of a broadened or distorted peak which may occur near the inlet of the column carries over to the final stage. Therefore, it is believed that, with any contrivance given to the gel layer in the central part or near the outlet, no improvement of the separation performance can be attained. Accordingly, it is customary practice to use the means of supplementing a high activity gel to the inlet side of the column.